/*
 * Copyright (C) 2018 The Sylph Authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package ideal.sylph.runner.flink.udf;

import org.apache.flink.api.common.typeinfo.TypeInformation;
import org.apache.flink.api.common.typeinfo.Types;
import org.apache.flink.table.functions.ScalarFunction;
import org.apache.flink.types.Row;

/**
 * udf
 */
public final class RowGet
        extends ScalarFunction
{
    public String eval(Row row, int i)
    {
        if (row == null) {
            return null;
        }
        Object value = row.getField(i);
        return value == null ? null : value.toString();
    }

    @Override
    public TypeInformation<?> getResultType(Class<?>[] signature)
    {
        return Types.STRING;
    }
}
